Indicating device for thermal cut-outs



C. F. P. CARRIER.

INDICATING DEVICE FOR THERMAL CUT-CUTS.

APPLICATION FILED APR. 28, |920.

1,368,482.l L y Panwa Feb. 15,1921.

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UNITED STATES i PATENT, oFEicE.

CABL F. P. CARRIER, OF PHILADELPHIA, :PENN SYITA.1\I'IA.` i

INDICATING DEVICE FORl .THERMAL CUT-CUTS.

Toall whom 'it mayco'rwem:

Be it known that I, CARL F. wP.(}Aiziuiiii, citizen of the United States, residing at Philadelphia in the county of Philadelphia and lState of Pennsylvania, have invented certain new and useful Improvements in In- Specification of Letters Patent. i

dicating Devices for Thermal Cut-Outs, o f y mation for the renewals of the ruptured element. A

A still further object of my invention is the provision of means forming an accessible and compact part of the lamp/socket, said means being adapted for repeated renewals of the fusible element and which also carry p the renewal fuse unit.

Further ob'ects of my invention relate to various details ofconstruction and arrangement of parts hereinafter described and par ticularly set forth in the accompanying drawings, wherein:

Figure 1 is a side elevation, partly in section, illustratin my invention adaptedvfor use wherever used. r y

Fig. `2 is a side elevation, partly in section, illustrating my invention adapted for use wherever cartridge type fuse units are n used.

Fi L3 illustratesy my invention slightly modi ed to adapt it to one form of standard fitting. 'K

Fig. 4 illustrates my invention slightly modified to adapt it to another form of standard fitting.

Fig. 5 is an'end 'elevation of Fig. 4.

Fig. 6 illustrates my invention as adapted plug type fuse units arey Patented Feb. 15, 1921.

Application med April 28, 1920. Serial No.`77,248.

to lise wherever thermal cut-outs are used to vindicate or open an electric circuit when a predetermined degree of heat is reached v external to the circuit; and- Fig. 7 'is a detailed view of the thermal unit illustrated in operative position in Fig. 6. v

usible cut-outs as commonly employed in electrical work, consist of a short length -of fusible material, electrically connected at its ends to suitable terminals, and the lfusible material inclosed within a shell of noncombustible insulating material. It is also common practice to substitute for the fusi'- ble material, a length of non-fusible conducting material secured'at its ends to terminals by readily fusible solder. In each case, however, the fuse element operates to break the circuit between the terminals when a predetermined degree of heat is reached; such heat obviously occurring from an overload on the line, or from an external source, as for instance, when a fuse unit is mounted on a journal box, motor housing, etc. 4

To comply with the re uirements `of the lire underwriters, the fusi le element must necessarily be inclosed, and much diiiculty is therefore experienced in ascertaining whether or .not the fusible element is ruptured, for itwill be readily appreciated that when a plurality of fuse units are employed in a series of related circuits, as is generally the case, it is an exceedingly troublesome and time-consuming practice to locate a blown or ruptured fuse, since each fuse unit must be removed, and the circuit tested.

On locating the blown fuse, it is either replaced by a new fuse unit, or the ruptured fusible element is removed from the shell l and a new length of fusible material' inv more desirable in `use in Asertecl between t e terminals; or said fusible element may be resoldered in order to complete the circuit. The latter methods are that the renewing operation requiresI little or no experience or expense, and the necessity of maintaining a supply of vfuse units in reserve for immediate `use is thus obviated.

It will also be noted, that when tlamps are wholly depended upon for the illumination of switch boards, circuits, etc., a ruptured fuse in the lamp supplying circuit will present further difficulties, and dangers, since the blown fuse must be located and repaired in the dark.

Numerous attempts have heretofore been made to provide a fuse of this character with suitable indicating means whereby an attendant may tell at a lance the condition of the fusible element. he results of such attempts, however, have not proven wholly satisfactory, due to their complicated construction, their unreliability, and the consequent diiliculty of use and expense of manufacture. v

To obviate the above referred to disadvantages and provide numerous advantagesl heretofore unattainable with indicating fuse x1, through which the lead terminal 8 extends and is insulated therefrom by a removable `diaphragm 9 of any suitable,y insulating material.

Screw threads 10, are formed on the klead` terminal 8, on which a thumb nut 11 opcrates tol engage and clamp one end of a length of fusible material'12, theother end of the fusible element, being clamped between thevremovable insulating diaphragm 9 and the lead terminal 7 It will thus be seen that a circuit is completed between the lead terminals 7 and 8.

. through the fusible element 12, and that the terminals 5 and 4, are connected in parallel with the lead terminals 7 and 8.

In operation, the current sup lied to a circuit in which the lead termina s 7.and 8 are connected, normally traverses the fusible element 12. If, however, for any reason, an over-load occurs in the circuit and causes the fusible element 12 to blow, the current is shunted through the filament 13 in the lamp 6. The illumination of the lamp 6 indicates that the fusible element is ruptured, andthe lamp remains lighted until the fusible element is renewed.

To facilitate the renewal of the fusible element 12, I provide 'aV bobbin 14, forming an extension o f the lamp socket 1` on whichV fusible material 12al is wound in reserve for repeated renewals of the fusible element, sultable lengths of the' fusible material 12" being severed'from the supply on the bobbin 14 when needed,.and connected to the lead terminals 7 and 8, as above described.

-the lamp socket-1b, being My invention is also applicable'to. numer-4 ous embodiments, as illustrated in Figs. 2- to 6.

In Fig. 2, a standard type of renewable cartridge fuse consisting of a cylindrical insulating shell 15, having terminals 16 and 17 is adapted toconnect a suitable length of 4fusible material 12 between the terminals 16 and 17, which are respectivel connected with the lead terminals 8a an 7?* of the lamp socket 1*. The insulating shell 15 is removably secured in-the terminals 16 and 17, by a screw-threaded plug 18, which engages screw threads 19 on the inner diameter of the terminal 16.

In Fig. 3, I have illustrated my iii-vention as applied to a standard plural lamp socket, comprising a llamp socket 1", and a fuse socket 19, the fusesocket-19 forming a portion thereof and extending at right angles thereto, the terminals 2b and 3b of respectively connected with the lead terminals 7 b and 8b, and the terminals 2 and 3 of the fusesocket 19 being connected in arallel with the terminals 2b and 3". A use uni `.20 having terminals v21 and 22, adapted to respectively connect with the terminals 2 and 3 of the fuse socket 19, is preferably of the standard plug type having a fusible element indicated at 12b connecting the terminals 21 and 22.

In Figs. 4 and 5, I {have illustrated my invention slihtlv modified to permit the adjacent the base of the lam socket 1, with the terminals 2c and 3cof t e lamp socket, the fuse unit 23 comprising a shell of insulating material, through which extends a fusible element indicated at 12, and connected at its ends with the terminals 26 and 27 of the fuse unit 23. Depending from the base of the lamp socket 1c is a springvclip -having resilient arms 24 and 25, the arms 24 and 25being adapted to engage the insulating shell of the -"fuse unit 23, and retain the terminals'26 and 27 in contact with the resilient terminals 7 9 and 8, respectively, of the lamp socket 1.

In the figures above described, I have illustrated my invention asadapted to be used -in electrical circuits wherever a fuse unit is required for the protectionof the circuit against overload, or an excess of current arising from any source. In4 Fig. 6, however, m'y invention is illustrated as applied to thermal cut-outs, where the thermalelement operates tol break or open a circuit, and to indicate when apredetermined degree of heat is reached; such heat bei generated at a point external to the circuit. I have illustrated my'invention as adapted for attachment to journal lamp 6. Ahollow base member 28 is connected to the lamp socket l, and is provided with perforated bosses 29 and 30, in which retaining means such as bolts are adapted to: clamp the base 28 to such'apparatus as above mentioned.

Lead wires 3l and 32 connectedto a source f of electricity extend through perforation's 1n the base member 28, and are connected respectively with the terminals 33 and 34. S ots 35 and 36 are respectively formed in the terminals 33 and 34, in which screws 37 and 38 operate to retainl the terminals in position in the base 28. A block ,of insuating material 39, in which the screw 37 is threadedserves to insulate the terminal 33 from the base 28, respectively connecting' the terminals 2d and 3d of the lamp socket l, and extending downwardly therefrom are a pair of lead terminals 40 and 41, said lead terminals 40 and 41 `being formed of resilient conducting material and adapted to contact the upper surfaces of the termi.- nals 33 and 34- respectively. I

A fuse element 12d which is shown by illustration as a non-fusible link connected at its ends with the terminals 33 and 34 by readilyfusible solder 42, is adapted to no1'- mally complete the circuit between the terminals 33 and 34. i

It will be readily understood from the foregoing that when a; predetermined degree of heat is transferred tothe terminals 33 and 34, from the base 28, the solder42 will melt, releasing the link 12d g and 34,* The link 12t1- will then drop under the force of gravity through the -hollow base 28, asindicated in 4dotted lines and open they circuit between the lead wires 3l and 32, shunting the current through the lamp 6, as above described.

I am aware that some changes other than those already indicated, may be made in the various arrangementand combinations of the several devicesand parts, as well as the details of construction thereof, without del. partin from the scope of my present inveny tion. ence I do notl limit my invention to the exact arrangements and combinations of vsaiddevices and parts as described in the foregolng specification, nor do I confine myhself to the exact details of the-construction as illustrated in the accompanyin drawing, 'it being appreciatedv that those s 'lled in the art may-makeyarious of said parts from the terminals 33 modifications without departing from the ,Y

spirit of my invention.- v

Having thus described my invention what I claim 'as new and desire to secure by Letters Patent is l. In a device lof the character described, in combination, a lamp socket having lead fterminals, and

in combination, a lamp socket having leadv terminals, and a thermal cut-out carried by said lamp socket, said thermal cut-out comprising a fusible element adapted to bridge the lead terminals on said lamp socket.

3. In a device of the character described,

in combinationfa lamp socket having lead terminals, a thermal cut-out carried by said lampsocket, said thcrmal cut-out having terminals connected in arallel with said lead terminals, a fusible e ement bridging said terminals, and means for renewing said fusible element. i

4. In a' device of the character described, in combination, a lamp socket, lead terminals carried by said lamp socket, and a thermal cut-out connected in parallel with and carried by said lead terminals.

5. In a device of the charactery described, in combination, a lamp socket having.v lead terminals, a -fuse unit comprising a fusible element connected in parallel with said terminals and carried by said lam socket, and means for repeatedly renewing sai fusible element.

6.' In a device of the character described,

prislng a bobbin` mounted on said lamp socket and fusible material carried by said bobbin.

7 A device of the character described, in combination, a lamp socket, a fuse unit, and means for renewing said fuse unit, said lamp socketr having lead terminals,v terminals on 'sa-id fuse unit, a fusible element connecting i said terminals, which are in turn connected in arallel with said lead terminals, and

fusible material carried by said lamp socketr for renewing said fuse unit.

In a device of the character described,

whereby in combination, a lam socket and a lamp, lead terminals connecting said lamp socket,

a fusey unit connected in parallel with said lead terminals, comprising terminals, and a' said terminals, fusion of the fusible "element will operate to light said lamp, and means carried fusible element connectin by saidlamp socket and operable to renew said fusible element and 'extinguish said lamp.

9. 'ln a device of the character described, in combination, a lamp socket having terminals, a fuse socket formed in piece therewith and having terminals connected in parallel 5 with the terminals in said lamp socket, a

plug fuse having terminals adapted to contact said terminalsl in said fuse socket and lead terminals on said lamp socket connected in parallel with saidterminals in said fuse 10 socket.

10. In a device of the characterdescribed, in combination, a lamp socket havin terminais, resilient conductors carried y said socket and connected with said terminals, a fuse unit having terminals adapted to con- 15 tact said resilient conductors and means detachably securing said fuse unit to said soket.' h f I f n testimon .W creo a X, siature.

- y CARL F. P. (IlllRlgInER. 

